Roots of the European and northern Asian herb Valerian (Valeriana officinalis), are well known for their relaxant and anxiolytic properties, and usefulness in the management of insomnia and mild anxiety. Clinical trials into its effects on insomnia and sleep problems including in menopausal women and patients withdrawing from benzodiazepine drugs, have generally reported favourable findings(1-4).
As with all medicinal plants, a single useful application is a far-fetched concept, and Valerian is no different in this. Apart from being pleasing to some cats in a similar way catnip is, another increasingly supported application for this well known herb, is to help support cognitive function.
Conventional sleeping tablets such as triazolam and zopiclone have detrimental effects on cognitive function(5,6), but comparative studies found valerian to show no such negative effects(1, 7). Next day hangover like symptoms and cognitive deficits are relatively frequent adverse events of all drug-based anti-anxiety or sedative agents, so this itself is a significant valerian advantage. However, evidence that valerian may additionally protect against cognitive decline or enhance cognitive functions in other settings, is of interest.
Early indications of cognitive enhancing effects of valerian particularly in the elderly, came from a Korean study in aged mice published in the journal Exp Gerontology(8). Following 3 weeks of valerian root administration (and valerenic acid), improvements occurred in several behavioural parameters indicative of improved cognitive functions, including exploration of new objects, escape latency, and swimming speeds. These effects were accompanied by enhancement in nerve cell differentiation and neuroblast differentiation, and reduced serum levels of corticosterone, in the valerian versus control treated mice. While an animal study, these findings suggest similar cognitive promoting effects in elderly humans.
Since then, at least two human clinical studies have measured changes in cognitive function following valerian administration. These include a study with 39 patients on haemodialysis whose cognitive status improved after taking valerian 60 minutes before bedtime for one month(9). The prevalence of cognitive disorders in kidney failure patients undergoing haemodialysis is twice as high as the general population, and these are often undiagnosed(10). Neuroprotective properties, as reported for ethanolic extracts of valerian in animal studies, may be contributory to such benefits(11, 12).
Another study explored cognitive dysfunction in 61 patients aged between 30 and 70 years, scheduled for elective coronary artery bypass surgery(13). Patients received either valerian or placebo capsules twice daily for 8 weeks following surgery. Cognitive brain function was evaluated prior to surgery and at 10-day and 2-months following, using the Mini Mental State Examination (MMSE) test. In the valerian treated patient group the mean MMSE score decreased from 27.03 ± 2.02 in the preoperative period to 26.52 ± 1.82 at the 10th day, and then increased to 27.45 ± 1.36 at the 60th day. Conversely in the placebo group, scores reduced from 27.37 ± 1.87 in the preoperative period to 24 ± 1.91 at the 10th day, and rose only slightly to 24.83 ± 1.66 at the 60th day. With post-operative cognitive decline now recognised as a negative outcome in many patients undergoing this increasingly common surgical procedure(14), the finding that valerian may prevent this, has implications for coronary artery bypass as well as potentially other forms of surgery.
Valerian is also used traditionally for digestive or menstrual cramps, and for nervous headaches(15, 16). Prior to the development of early tranquilliser drugs such as barbiturates, or when these weren’t accessible, it was also a valued intervention in the management of some forms of pain.
Support for these historical applications has emerged recently from results of a clinical trial in Iran which investigated the effects of valerian on tension headaches. These present as dull pain, tightness, or pressure around the forehead or back of the head and neck, and are the most common type of headache.
The study included 88 participants with tension-type headache, randomly assigned to take valerian or placebo capsules twice daily after dinner for a month. After this one month treatment, valerian was associated with a significant reduction in the negative impacts of headaches on daily living and disability, and a reduction in the severity score, relative to the placebo group(17).
Finally, as anti-anxiety and sedative drugs can impart clinical improvement in some patients with depression, and potential antidepressant activity has been implicated for valerian in an animal model of depression associated with chronic stress(18, 19), beneficial applications in some patients with depression, are possible. Depression can also be accompanied by cognitive disturbances and a compromised memory. As such, herbs such as ginkgo and valerian for which benefits on associated cognitive function have been shown, may offer additional effects beyond those of antidepressant herbs and drugs, in the management of patients with depressive illness.
- Dorn M. Forsch Komplementarmed Klass Naturheilkd. 2000 Apr;7(2):79-84
- Poyares DR et al, Prog Neuropsychopharmacol Biol Psychiatry. 2002 Apr;26(3):539-45
- Ziegler G et al, Eur J Med Res. 2002 Nov 25;7(11):480-6.
- Taavoni S et al, Menopause. 2011 Sep;18(9):951-5.
- Gunja N. J Med Toxicol. 2013 Jun;9(2):163-71.
- Stranks EK et al, J Clin Exp Neuropsychol. 2014;36(7):691-700
- Hallam KT et al, Hum Psychopharmacol. 2003 Dec;18(8):619-25.doi: 10.1002/hup.542.
- Nam SM et al, Exp Gerontol. 2013 Nov;48(11):1369-77.
- Samaei A et al, BMC Nephrol. 2018 Dec 27;19(1):379
- Erken E et al, Clin Nephrol. 2019 May;91(5):275-283
- Malva JO et al, Neurotox Res. 2004;6(2):131-40.
- De Oliviera DM et al, Neurochem Res. 2009 Feb;34(2):215-20.
- Hassani S et al, Psychopharmacology (Berl). 2015 Mar;232(5):843-50.
- Ngcobo NN et al, S Afr J Psychiatr. 2020 Jul 9;26:1470.
- Rudolf Fritz Weiss, Herbal Medicine, published by Volker Fintelmann 1998
- Barker J. The Medicinal Flora of Britain and Northwestern Europe. Winter Press, West Wickham, Kent, UK, 2001. ISBN 1 874581 630
- Azizi H et al, Avicenna J Phytomed. May-Jun 2020;10(3):297-304
- De Brito APA et al, Front Neurosci 2020; 14:759.
- Kandilarov IK et al, Folia Med (Plovdiv) 2018; 60(1):110-116.